Pipe Ramming Under Rail Tracks in California

Contractors like Bill Malcolm, president of Utility Boring, Inc., out of Bloomington, California, have learned some valuable lessons in the hard-knock world of underground utility construction. The chief lesson he's learned is to have a full line of tools in his tool kit as he tackles installation projects. That way, he can not only get the jobs done but get them done profitably and in a way that meets the requirements of his customers.

To own multiple technologies and have the crews trained and experienced enough to successfully use them takes the willingness to try new technologies, the faith in your crew's ability to use them, and the knowledge and experience in knowing which to apply in a given situation.

According to Malcolm, experience plays a large part in his deciding how to deploy his crews and his equipment. "The economics and customers' requirements are the determining criteria. We have auger boring equipment, old flat boring machines, horizontal directional drilling equipment and pneumatic tools. They all have their special applications, and we want to have the machines on hand when we need them."

Utility Boring, Inc., has been an underground utility contractor since 1984, and Malcolm has been in the business longer than that. Currently, the company runs six crews that move up and down the Pacific coast states employing their eight horizontal directional drilling rigs, auger boring machines and pneumatic tools.

"We split off the auger boring machines into a separate division since the work they do seemed so radically different than the other underground work we've been pursuing," stated Malcolm. "Most of what we do involves horizontal directional drilling. We started horizontal directional drilling in the early nineties."

Utility Boring, Inc., needed all the tools in their toolbox on a recent job in southern California. With C. R. Frederick as the primary contractor, Utility Boring, Inc., as a first tier subcontractor was responsible for all the road and railroad crossing work on the 37-mile fiber-optic conduit job. It stretched from Victorville in the high desert south through the San Bernardino National Forest, through the city of Fontana, under major interstates 15 and 10, and over to the Ontario, California, airport.

"We've had plenty of delays on this project," explained Malcolm. "The state forestry department wanted to give some extra breeding time to a certain bird in the mountains. It seems the El Niño weather delayed their nesting patterns. As a result, the forestry people did not want any noise this winter or early spring above 80 decibels in the mountains during their breeding. Fortunately, we were able to complete the part of the project under the interstates during that delay period."

As a condition of granting the right of way through the San Bernardino mountains, the department also stipulated that only one major utility line permit would be issued in order to forestall any further potential disruption of animal or aviary habitat. As a result, during one segment, Utility Boring, Inc., pulled in a number of asset owners' conduits, enlarging a single bore wall to accommodate twelve 2-inch ducts, and twenty-four 1.25-inch conduits.

One of the crossings in this project involved putting the line under a railroad spur line. Since the line was an active one, the railroad was determined not to have any problems. So it was fortunate on Malcolm's part that he had the tools to be able to satisfy the railroad's demands.

When someone wants to put new utility lines under the roadbed, railroad officials must determine how and when it will be done. After all, it's their vital railbed property that's being cut through.

That was why Malcolm chose to use the HammerHead Mole pneumatic pipe-ramming tool. Railroads are increasingly taking note of pipe ramming as an excavation tool when casings need to cross their lines. They do not have to worry about interruption of service, voids during construction or post-project settlement.

Although Utility Boring, Inc., was an experienced auger boring contractor, auger boring was ruled out. If they used conventional jack and bore methods, they would have to keep the auger head under the lead edge of the pipe. While that would prevent any voids from being created and from threatening the integrity of the railbed, it would have made the jacking all but impossible. That is why Malcolm turned to pipe ramming with a 7-inch pneumatic tool for the 10-inch steel casing that would house the six 2-inch conduits.

To accomplish the pipe ramming, the crews spent one day preparing a launch pit, shoring the sides of the pit with steel trench shoring. The casing was to be rammed 10 feet below the grade of the railroad tracks. "Since we had done so many directional bores on this job," described Malcolm. "I might have preferred to use one of the Vermeer horizontal directional drilling machines that we own. But there wasn't enough set back space to level out the shot. Whenever we can eliminate the construction of a pit, we like to simply because of the economics involved. It does take time to dig the pit, level it and shore it. But having the pneumatic tool to do the ramming allowed us to get the job done. It was a perfect application in this case."

The 7-inch HammerHead Mole tool was lowered into the pit, and it locked itself into the collets nested inside the 10-inch casing. Sixty feet in all of the casing was rammed in 10-foot segments underneath the railroad. Total ramming time (not counting welding the casing segments) was 90 minutes.

"We're looking for more opportunities with the right pricing strategy for pipe ramming," stated Malcolm. "We know it fits in with the rest of the underground installation equipment that we have. In the end, we know that the length, depth, project conditions, price, and the demands that different authorities place on us are all important factors to consider. We also know that we need to have all the tools necessary for any job."